A variety of stuides of clinical disorders of male reproduction are in progress. These include 1) studies of the hormonal regulationof spermatogenesis in hypogonadotropic men, 2) analysis of biochemical parameters of sperm metabolism in men with non-motile sperm, 3) longitudinal evaluation of the adverse effects of cytotoxic drugs on testicular function in men receiving chemotherapy formalignant disorders, and 4) the evaluation of treatment of men with idiopathic infertility.